Can't connect with Wired Connection. HELP

Hey guys/gals. I am trying to connect my Wii to the internet with a wired connection. I have my router and everything set up correctly since I can connect to xbox live without any trouble. I bought a rocketfish lan adapter and it says it works for the Wii. I keep getting the error code 51420 and just do not know what to do. I can connect using Wirless but would prefer Wired. Hope you can help. Thanks

if your 360 is fine then the only problem could be the cable...check if its loose or hase holes in it...try another cable....if thats not it then maybe its you lan adaptor...maybe you should have bought the offcial lan adaptor.. here http://store.nintendo.com/webapp/wcs/stores/servlet/ProductDisplay?productId=117712&